A gas turbine includes an air compressor that generates compressed air by compressing outside air, a combustor that generates combustion gas by combusting fuel in the compressed air, and a turbine that is driven by the combustion gas. A combustion liner of the combustor, blades and vanes of the turbine, etc. are exposed to the high-temperature combustion gas. Thus, in the gas turbine, it is necessary to cool these hot parts so as to protect these hot parts from the heat of the combustion gas.
Patent Literature 1 below discloses a cooling system for cooling a combustion liner of a combustor that is one of hot parts of a gas turbine. This cooling system includes a cooling air line that guides compressed air compressed by an air compressor of the gas turbine to the combustion liner, a cooler that cools the compressed air in the cooling air line, and a booster that pressurizes the cooling air in the cooling air line.